Marcelo Bielsa's men could have strengthened its grip on top spot with a home win over the league's bottom club Luton Town but was held to a 1-1 draw.
Substitute Harry Cornick gave Luton a surprise 50th-minute lead, only for Stuart Dallas to respond 13 minutes later.
West Brom can cut Leeds' advantage to one point with victory in its midweek trip to Sheffield Wednesday but will be looking over its shoulder at surging Brentford.
The Bees made it three wins from three since the resumption of the season - and four in four - goals from Bryan Mbeumo, Josh Dasilva and Joel Valencia securing a 3-0 defeat of Reading that moves them within two points of the Baggies in the second automatic promotion spot.
Fulham is two points further back after Cyrus Christie's 75th-minute effort earned a 2-1 triumph over west London rival QPR.
Kai Naismith scored twice as Wigan Athletic moved eight points clear of the relegation zone following a 3-0 win over struggling Stoke City.
Barnsley is only a point adrift of safety after beating Blackburn Rovers 2-0 while elsewhere Cardiff City drew 0-0 with Charlton Athletic and Millwall's clash with Swansea City ended 1-1.